As illustrated in FIG. 1, a pixel of an active-matrix organic light emitting diode (AMOLED) display includes a plurality of Thin Film Transistors (TFTs) and a plurality of capacitors due to a characteristic of current driving of the organic light-emitting diode (OLED). FIG. 2 illustrates the arrangement of such pixels. However, a design of a pixel circuit has to be improved due to an increasing demand on the display performance, which is a challenge in the industry. As illustrated in FIG. 3, for example in the related art, a via hole for overlapping and connecting a cathode and an anode is filled with a pixel definition layer, so as to improve the overlapping of the cathode and the anode through the via hole and prevent from a risk of short circuiting caused by metal climbing in the via hole. However, such arrangement may reduce an aperture ratio, as illustrated in FIG. 4.
Furthermore, as illustrated in FIG. 5, the capacitor may be of a smaller capacity due to an increment of pixels per inch (PPI). As illustrated in FIG. 6, in the related art, it is arranged the metal3 which is a metal material not belonging to a gate electrode metal layer or a source-drain electrode metal layer for increasing the capacity of the capacitor. However the aperture ratio is still reduced in such arrangement.
In other words, the aperture ratio has to be reduced due to the improvement of the pixels.